The U.S. Department of Homeland Security is seizing domains and taking down URLs in the name of copyright infringement, but its tactics are worrying certain members of Congress.

In a letter (pdf) sent last week to Attorney General Eric Holder and Secretary Janet Napolitano, three members of the House Judiciary Committee aired their unease.

“We are concerned about your Departments’ seizure of domain names under Operation In Our Sites, launched in November 2010,” the letter said. “Our concern centers on your Department’s methods, and the process given, when seizing the domain names of websites whose actions and content are presumed to be lawful, protected speech.”